The invention is directed to a steam generator for creating steam for use in cooking equipment, particularly for table-top or footed equipment working in combined operation using hot air and hot steam for gastronomy, industrial kitchens and the like. The generator comprises a water-filled boiler that in turn comprises an automatically level-regulated water admission, a steam discharge for the automatic introduction of hot steam into the cooking space of the cooking equipment as needed and a heating mechanism operating in intervals, for example, in the form of heat exchanger surfaces which are heated electrically or with gas heating, and a decalcification means having a water outlet means arranged close to the floor and to the side wall of the boiler for at least partially emptying the boiler as needed for the purpose of flushing off lime particles that have flaked off and have been collected at the floor of the boiler.
There is the problem in such steam generators, which are normally exposed to high thermal stresses as a consequence of intense employment of the appertaining cooking equipment, and this problem is that thick lime deposits form over time both at the heat exchanger surfaces of the heating means--i.e., at the corresponding heating rods or heating coils of electrically operated equipment and at the corresponding heat exchanger tubes in the case of gas-operated equipment. Lime deposits also occur at the boiler walls. These lime deposits must be removed from time to time since they impede the heat transmission at the heat exchanger surfaces; however, they must also be removed from the inside surfaces of the boiler since they can have negative influences on the quality of the generated steam because certain substances that, for example, can influence the properties of the generated steam in a negative way in view of the taste of the products to be cooked can become concentrated in these lime deposits.
It is known to remove the lime deposits in that the user of the cooking equipment dissolves the lime deposits at more or less regular intervals by introducing a chemically acting decalcification means into the boiler and heating outside of normal operation. These lime deposits, for example, are then discharged through a drain cock specifically provided for this purpose while emptying the boiler.
A certain decalcification effect can also be achieved without introducing a chemically acting decalcification agent.
U.S. Pat. No. 1,616,372 discloses a cleaning mechanism for heating equipment that is composed of a flat chamber that is arranged at the floor of the heating equipment and is provided with a plurality of openings that are arranged such that, when a valve that is in communication with the cleaning chamber is open, the out-flowing agent can eliminate the deposits in the heating device through the cleaning chamber. What is thereby exploited is that a certain over-pressure prevails in the heating equipment. The decalcification effect, however, is not satisfactory. This is due, first, to the fact that it is necessary for the user to in fact effect the decalcification at certain intervals by actuating the drain cock, a measure that is frequently omitted as a consequence of carelessness. Further, the pressure arising in the equipment of the initially stated species is quite inadequate for reliably eliminating the sediment particles. Moreover, only lime particles that are easily detached from the heat exchangers, or, respectively, from the inside surfaces of the boiler proceed into the cleaning container. Firmly adhering lime particles continue to lead to the impediments that were set forth above.
It is also known to employ a drain cock as water outlet means in order to eliminate the lime particles from time to time that collect at the floor of the boiler in the form of small particles. However, the flow that arises when emptying the boiler is definitely not adequate to convey the lime particles deposited at the floor of the boiler out through the drain cock. On the contrary, the drain cock is usually already plugged briefly after the start of a decalcification process, i.e., after the drain cock is opened, so that the lime deposits cannot be reliably eliminated. Further, the lime particles entering into the interior of the drain cock and into its closing mechanism plug these up to an increasing degree due to the lack of an adequate rate of flow of the out-flowing water, so that an effective decalcification is no longer guaranteed after a relatively short operating time.